NEW YORK (CBSNewYork) – A legal battle over the Bronx Zoo elephant heads back to court today.

The Nonhuman Rights Project says the zoo has been keeping the 48-year-old elephant named Happy inside a roughly one-acre exhibit for more than 40 years, 13 of which she has spent alone.

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The animal rights group wants Happy to be moved to a private sanctuary where she can be with other elephants.

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The zoo, however, believes Happy could face conflict if she lives with others.

A spokesperson has said, “Happy is content in the home she’s known for nearly four decades.”

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An online petition to transfer the elephant received more than one million signatures.